The present invention relates to a sheet-like structure material having an intermediate resin layer between two adherends such as glass sheets. The invention also relates to a method for manufacturing the sheet-like structure material.
Known laminated glass is formed from two sheets of plate glass with an adhesive film between, the whole being laminated together by thermocompression bonding. In such laminated glass 51, the edge ends of glass sheets 52, 53 around the periphery are uncovered as shown in FIG. 5(a).
The glass sheets are liable to break off if a something strikes against their uncovered edge ends. When such laminated glass 51 is fit into a framework 54 such as a metallic sash as shown in FIG. 5(b), the edge ends of the glass sheets 52, 53 come into direct contact with the framework 54. In this condition, if the framework 54 is rapidly cooled, the grass sheets 52, 53 will be cracked because of the difference in temperature between the edge ends and center of each glass sheet. Note that reference numeral 55 in FIG. 5(b) represents a rubber seal.
To solve this problem, when the laminated glass 51 is fit into the framework 54 such as a metallic sash, a setting block (heat insulating block) 56 is usually placed under the laminated glass 51 as shown in FIG. 5(c), thereby interrupting heat transmission between the glass sheets 52, 53 and the framework 54.
However the setting block process is employed, there still remains the risk of braking the unprotected edge ends of the pane during transportation and handling. Further, the conventional method shown in FIG. 5(c) requires the installation of the setting block, resulting in complicated fitting process. Another disadvantage is that when applying finishing treatment to the laminated glass according to the conventional process, it is very troublesome to chamfer the edge ends of the laminated glass and particularly to finish the gradually changed edge from round cut corner to the straight cut in the laminated glass.
The present invention is directed to overcoming the foregoing problems and it is accordingly a primary object of the invention to provide a sheet-like structure material and its manufacturing method, the sheet-like structure material being capable of absorbing impact imposed on its edge ends to protect its adherends and requiring much less labor for installation work and end face treatment.
The above object can be achieved by a sheet-like structure material embodying the invention, wherein an outer peripheral structure having elasticity is integrally formed at the outer periphery of a sheet-like composite body comprising a first adherend, a second adherend and an intermediate resin layer sandwiched between the first and second adherends.
According to the invention, the outer periphery of a sheet-like composite body comprising two adherends and an intermediate resin layer is integrally surrounded by an outer peripheral structure having elasticity. With this arrangement, even if impact is imposed on the edge ends of the sheet-like structure material such as laminated glass, the impact is adsorbed by the outer peripheral structure, thereby protecting the sheet-like composite body. Further, the edges of the adherends do not hurt the workers who deal with the sheet-like structure material. When setting the sheet-like structure material in a framework such as a sash, the adherends such as glass do not come into direct contact with the framework, which brings about heat insulating effects. Therefore, even if the framework is rapidly cooled, the edge ends of each adherend will not differ from its center in temperature, so that there is no danger of cracking the adherends. When setting the sheet-like structure material of the invention in a framework or when applying chamfering treatment to its edge ends, no complicated process is involved. It should be noted that the thickness of the outer peripheral structure can be arbitrarily determined according to the size of the framework.
In the invention, the outer peripheral structure may be formed from a resinous material from which the intermediate resin layer is to be formed and which is oozing from between the first and second adherends. With this, not only can the outer peripheral structure be formed with ease, for example, by injection and press molding but also the outer peripheral structure can be easily adhered to other outer peripheral members since the resinous material of the outer peripheral structure serves as an adhesive agent. In this injection and press molding, the intermediate resin layer and the outer peripheral structure are formed by spreading the molten resinous material through uniform application of pressure to the whole molten resinous material. The molded product produced by this method is free from defects in joining the adherends to the resin layer. Additionally, no stress strain is generated in this method since the resin layer is formed by uniformly applying pressure to the whole molten resinous material so as to cause the material to spread. The outer peripheral structure may be formed from only the same resinous material as that of the intermediate resin layer. In this case, the outer peripheral structure and the sheet-like composite body can be molded at the same time, which simplifies the molding process. Alternatively, the outer-peripheral structure may be composed of a part formed from the same resinous material as that of the intermediate resin layer and a part formed from a resinous material different from the resinous material of the intermediate resin layer. This alternative embodiment can be put in practice by only interposing a member (i.e., outer peripheral member), which is made of a material different from the resinous material of the intermediate resin layer, between the dies during molding so that the outer peripheral member is easily formed in an integral manner. This makes it possible to produce highly value-added products through a simple molding process.
Preferably, the resinous material of the intermediate resin layer is a thermoplastic resinous material having a tensile elastic modulus of 1,000 kg/cm2 or less. Use of such a thermoplastic resinous material can prevent the adherends such as glass from breaking even if the resinous material contracts or expands owing to changes in temperature. The thermoplastic resinous material is selected from thermoplastic elastomers (TPE) including polyvinyl butyral (PVB), ethylene-vinyl acetate copolymer (EVA) and thermoplastic polyurethane (TPU). These materials are preferable, particularly when forming the outer peripheral structure and the intermediate resin layer from the same material.
Preferable examples of the material different from the resinous material of the intermediate resin layer include neoprene rubber, wood, neoprene rubber foam, urethane foam, polypropylene foam and polyethylene foam. Use of a material selected from the above examples allows the resultant sheet-like structure material to be used in various applications.
The first and second adherends may be formed from the same material or different materials selected from inorganic materials such as glass and silicon and from organic materials such as polycarbonate and acrylic resin. Use of such materials allows the resultant sheet-like structure material to be used in various applications such as the front glass, side glass and rear glass of automobiles and ordinary building materials.
According to the invention, there is provided a first method for manufacturing a sheet-like structure material, comprising the steps of:
placing a first adherend and a second adherend between dies in a compression molding machine so as to be in close contact with the dies respectively;
filling a mold cavity with a molten resinous material to integrally mold an intermediate resin layer and an outer peripheral structure, the intermediate resin layer being formed between the first and second adherends, the outer peripheral structure having elasticity and being formed at the outer peripheries of the first and second adherends and of the intermediate resin layer.
According to the above sheet-like structure material manufacturing method, the first and second adherends are placed between the dies of the compression molding machine and brought into close contact with the dies respectively, for instance, by vacuum suction. In this condition, the mold cavity is filled with a molten resinous material so that the intermediate resin layer is formed from this molten resinous material between the first and second adherends, integrally with the outer peripheral structure which has elasticity and is formed from the molten resinous material oozing from between the first and second adherends, enclosing the outer peripheries of the adherends and the intermediate resin layer. The configuration of the outer peripheral structure is thus formed by transferring a die pattern to the molding resin and therefore even if the finished pane shape has a round cut or straight cut shape, elaborate finishing can be easily accomplished by molded peripheral structure.
According to the invention, there is provided a second method for manufacturing a sheet-like structure material, comprising the steps of:
placing a first adherend and second adherend between dies in a compression molding machine so as to be in close contact with the dies respectively;
placing a preformed outer peripheral member at the outer peripheries of the first and second adherends;
filling a mold cavity with a molten resinous material to integrally mold an intermediate resin layer, an outer peripheral structure and an outer peripheral member, the intermediate resin layer being formed between the first and second adherends, the outer peripheral structure having elasticity and being formed at the outer peripheries of the adherends and of the intermediate resin layer.
In the above sheet-like structure material manufacturing method, the first and second adherends are placed between the dies of a compression molding machine and brought into close contact with the dies respectively, for instance, by vacuum suction. At the same time, a preformed outer peripheral member is placed at the outer peripheries of the adherends. In this condition, the mold cavity is filled with a molten resinous material. As a result, the intermediate resin layer is formed between the first and second adherends, from this molten resinous material. From the molten resinous material oozing from between the first and second adherends, the outer peripheral structure having elasticity is formed so as to enclose the outer peripheries of the adherends and of the intermediate resin layer. The outer peripheral member is adhered to (combined with) the outer peripheral structure so that the adherends, the intermediate resin layer, the outer peripheral structure and the outer peripheral member are all integrated. This method can provide highly value-added products, by suitably selecting material and shape for the outer peripheral member.
In both of the above manufacturing methods, when filling the mold cavity with the molten resinous material, it is preferred to perform compression molding by clamping both dies so as to uniformly apply pressure to the whole molten resinous material, thereby causing the material to spread. With this arrangement, defects in joining the adherends and the intermediate resin layer can be avoided and no stress strain is generated because the intermediate resin layer is formed by spreading the molten resinous material through uniform application of pressure to the whole molten resinous material.